package demo1;

import demo2.MySingleLinkedList;

import java.util.List;
import java.util.Stack;

public class MySingleList {

    static class ListNode {
        public int val;//节点的值域
        public ListNode next;//下一个节点的地址

        public ListNode(int val) {
            this.val = val;
        }
    }

    public ListNode head;//表示当前链表的头节点

    /*public void createList() {
        ListNode node1 = new ListNode(12);
        ListNode node2 = new ListNode(23);
        ListNode node3 = new ListNode(34);
        ListNode node4 = new ListNode(45);
        ListNode node5 = new ListNode(56);

        node1.next = node2;
        node2.next = node3;
        node3.next = node4;
        node4.next = node5;

        this.head = node1;
    }*/

    public void display() {
        ListNode cur = head;
        while (cur != null) {
            System.out.print(cur.val + " ");
            cur = cur.next;
        }
        System.out.println();
    }

    //得到链表的长度
    public int size() {
        ListNode cur = head;
        int count = 0;
        while (cur != null) {
            count++;
            cur = cur.next;
        }
        return count;
    }

    //查找是否包含关键字key在单链表当中
    public boolean contains(int value) {
        ListNode cur = head;
        while (cur != null) {
            if (cur.val == value) {
                return true;
            }
            cur = cur.next;
        }
        return false;
    }

    //头插
    public void addFirst(int data) {
        ListNode node = new ListNode(data);
        node.next = head;
        head = node;
    }

    //尾插
    public void addLast(int data) {
        ListNode node = new ListNode(data);
        ListNode cur = head;
        if (cur == null) {
            head = node;
            return;
        }
        while (cur.next != null) {
            cur = cur.next;
        }
        cur.next = node;
    }

    //任意位置插入,第一个数据节点为0号下标
    public void addIndex(int index, int data) {
        if (index < 0 || index > size()) {
            System.out.println("index不合法");
            return;
        }
        if (index == 0) {
            addFirst(data);
            return;
        }
        if (index == size()) {
            addLast(data);
            return;
        }
        ListNode cur = findIndexSubOne(index);
        ListNode node = new ListNode(data);
        node.next = cur.next;
        cur.next = node;
    }

    //找到要index节点的前一个节点
    private ListNode findIndexSubOne(int index) {
        ListNode cur = head;
        while (--index != 0) {
            cur = cur.next;
        }
        return cur;
    }

    //删除第一次出现关键字为key的节点
    public void remove(int key) {
        if (head == null) {
            return;
        }
        if (head.val == key) {
            head = head.next;
            return;
        }
        ListNode cur = searchPrev(key);
        if (cur == null) {
            System.out.println("没有你要删除的数字!");
            return;
        }
        ListNode del = cur.next;
        cur.next = del.next;
    }

    //找到key的前驱
    public ListNode searchPrev(int key) {
        ListNode cur = head;
        while (cur.next != null) {
            if (cur.next.val == key) {
                return cur;
            }
            cur = cur.next;
        }
        return null;
    }

    //删除所有值为key的节点
    public void removeAllKey(int key) {
        if (head == null) {
            return;
        }
        ListNode prev = head;
        ListNode cur = head.next;
        while (cur != null) {
            if (cur.val == key) {
                prev.next = cur.next;
            } else {
                prev = cur;
            }
            cur = cur.next;
        }
        if (head.val == key) {
            head = head.next;
        }
    }

    public void clear() {
        this.head = null;
    }

    public void reversePrintList() {
        Stack<ListNode> stack = new Stack<>();
        ListNode cur = head;
        while (cur != null) {
            stack.push(cur);
            cur = cur.next;
        }
        while (!stack.isEmpty()) {
            ListNode top = stack.pop();
            System.out.print(top.val + " ");
        }
    }
}
